Device for detecting flaws on running threads



April 30, 1968 I F. ANDERS 3,380,134

DEVICE FOR DETECTING FLAWS ON RUNNING THREADS Filed June 16, 1966 2 Sheets-Sheet 1 INVENTOR A ril 30, 1968 F. ANDERS 3,380,134-

DEVICE FOR DETECTING FLAWS ON RUNNING THREADS Filed June 16, 1966 2 Sheets-Sheet 2 INVENTOR United States Patent DEVICE FOR DETECTING FLAWS 0N RUNNING THREADS Fritz Anders, Neumunster, Germany, assignor to Phrix- Werke Aktiengesellscllaft, Hamburg, Germany Filed June 16, 1966, Ser. No. 558,083 Claims priority, application Germany, June 19, 1965, P 37,086 11 Claims. (Cl. 28-64) ABSTRACT OF THE DISCLOSURE In a flaw detector for detecting flaws on running threads, a pair of plates are arranged with respective edge portions overlapping. Each overlapping edge portion is provided with a cut-out so that the cut-outs together define a thread passage of square cross-section in which the thread runs freely. A pair of springs maintain the plates in operative position but permit their deflection to an indicating position if a thicker thread portion passes through the thread passage. A quality control device is arranged to become actuated when the plates are deflected.

The present invention relates to a novel device for detecting flaws, such as thickened portions or slubs on running threads. The new device may be installed on winding machines or in the stretch field of a stretch spinning machine.

Known devices of this kind work either by means of changes in capacity of an electric circuit produced when a thickened thread portion moves by, or the thickened portion may interrupt a light beam which is being focussed at the path of the thread. Such devices actuate a counting device or a thread cutter by producing and amplifying a signal current in a known way. Yet, such devices are very sensitive to shocks and to fluctuations of the voltage supply which are inevitable in operation. Further, threading in of the thread is involved and time consuming in those devices.

It is an object of this invention to provide a shockproof flaw detecting device which is simple in construction and into which the thread is easily threaded.

With this object in view, the device according to the present invention mainly comprises support means and two deflectable plates mounted on the support means and having free, adjacent edge portions which define, e.g., by partially overlapping notches, a preferably square thread passage, larger than the cross-section of the thread, yet smaller than the cross-section of a thickened portion or slub on the thread. Furthermore, the device may comprise an indicating means or a thread cutter which is actuated by the plates whenever said plates are deflected by a fault in the running thread. Upon such a deflection of the plates the thread passage opens up so that the thickened portion can pass. Instead of square, the thread passage may also be, for instance, circular or elliptical.

The plates are normally held in an operating position in Which the thread passage has a minimum clearance for the thread by forces that have to be so small that a thickened portion, passing through the passage, will deflect the plates, e.g., by rotating or tilting them.

The small forces may be provided by weights, or the plates may be held by magnetic forces. Yet, springs that hold the plates against stops have worked best as their bias can be set to any desired value.

The length of a side of the square thread passage should be only slightly larger than the diameter of the thread running through that passage. If the plates are tiltable about parallel fixed axes, it is possible to adapt the passage to the thread being used by providing a set of plates of different lengths. Yet, it is better to make at least the axis of one plate, or of both plates, adjustable, that is shiftable, in a plane perpendicular to the run of the thread. Thus, the plates will overlap less or more according to the adjustment. If the free plate edges are provided with right angled notches, symmetrical to the longitudinal axes of the plates, the opening for the thread will stay square, no matter whether the passage has been widened or narrowed.

If a thick portion or a slub runs through the opening formed by the two plates, these plates will be deflected from their operating position in direction of the thread run, actuating by this deflection a quality control means, which may be a simple indicator, a device counting the flaws of each spool, or a thread cutting device which stops the winding machine and cuts out the faulty thread portion. The actuation of such devices may be produced mechanically, for instance, a deflected plate may release the latch of the thread cutter or an anchor may be moved which allows the toothed wheel of a counting device to advance. However, an electrical control has proven superior. The deflected plate closes a contact of an electric circuit and the current, flowing through this circuit when the contact is closed, may, after amplification, actuate the indicator, counting device or thread cutter.

The novel features which are considered as characteristie for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanyin g drawings, in which:

FIG. 1 schematically illustrates an arrangement using the device of the present invention; and

FIG. 2 schematically illustrates an embodiment of the invention.

As schematcially illustrated in FIG. 1, a thread 2 is drawn by a supply roll 3 from a spool 1 and passes through a stretching field 8 located between supply roll 3 and a drive roll 4. From the latter, the thread passes through a guide 5 and over a roller 6 to spool 7. The detecting device 9 according to the present invention, only schematically shown in FIG. 1 cooperates with a portion of the thread in the stretching field 8.

FIG. 2 shows the arrangement in further detail. The detecting device includes the plates 10 and .11 which are formed in overlapping edge portions thereof with right angled notches 26 and 27. These notches form together in partially overlapping position a square opening or thread passage 12 through which the thread runs. The plates 10 and 11 are mounted On support means for pivotal movement between an operating position in which the notched free edges thereof overlap each other and define a thread passage slightly larger in cross-section than that of the thread (shown in full lines in FIG. 2) and a deflected position (shown in dash lines) by means of parallel shafts 28 and 29 respectively fixed to and projecting with opposite ends thereof beyond the edges of the plates 10 and 11 which are opposite the notched edges thereof. The shafts 2'8 and 29 are respectively turn'ably mounted in bearings 13 and 14, only schematically illustrated in FIG. 2 and it is to be understood that bearings are provided on opposite ends of each shaft.

The arrangement includes further means for yielclably maintaining the plates 10 and 11 in their operating position 'and these means may include, as schematically shown in FIG. 2, spiral springs 21' and 22 fixedly connected at one of the ends thereof to the shafts 28 and 2 respectively and at the other end thereof to a support. The springs are biased to impart the shafts 28 and 29 a moment so as to yieldably hold the plates and 11 against fixed stops 23 and 24 respectively, fixed to nonillustrated supports and arranged so that the plates, when the top surfaces thereof engage the stops, will be held in the operating position.

Quality control means cooperate with the plates 10 and 11 so as to be actuated when the latter move from the operating to the deflected position.

Such actuation is preferably accomplished by electrical means and for this purpose the arrangement may include, as schematically shown in FIG. 2, levers v1.5 and 16 of electrically conductive material respectively fixed to and rearwardly projecting from the shafts 28 and 29 so that the levers will, when the plates are deflected, make contact with fixed contacts 17 and 18, respectively, arranged in an electic circuit which may include an amplifier 19 and arranged in such a manner that when the circuit is closed by engagement of the levers and 16 with the contacts .17 and 18 current will flow through the circuit and actuate a quality control device, known per se, 20, schematically indicated in FIG. 2. The device may be a simple indicator, a counter, or a device stopping the thread feed and cutting out a faulty thread portion. The specific construction of the control device does not form part of the present invention and therefore the device is only schematically indicated in FIG. 2. In order to adjust the cross-section of the thread passage 12, so as to adapt the device according to the present invention for use with threads of different diameter, the position of at least one, but preferably the position of both plates is adjustable in a direction to vary the overlap of the notched edges thereof. For this purpose, the bearings and the spring support of each plate 10 and 11 may be respectively mounted on support plates guided on an appropriate support for movement toward and away from each other. This support, is course, to be constructed so as not to impede tilting of the plates 10 and 1.1 in any adjusted position. Obviously the adjustment need only be small and the means for adjustment may also include a micrometer or similar arrangement properly marked so that the thread passage 12 may be easily adjusted for threads of various diameters.

The device above described operates as follows. A roller 25, adjustably mounted, guides the thread 2 centrally through the thread passage 12. If a thickened portion on the thread 2 enters forcibly the thread passage 12, the plates 10, 11 are deflected. This deflection of the plates results in closing of the electrical circuit by levers 15, 16 attached to the plates. The current then flowing through the circuit actuates, after amplification by the amplifier 19 the quality control device 20 such as an indicator, counting device or thread cutter.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of detecting devices differing from the types described above.

While the invention has been illustrated and described 'as embodied in the detecting device with two plates, it is not intended to be limited to the details shown, since various modifications and structural changes may be made Without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A device for detecting flaws such as thickened portions or slubs or running threads comprising, in combination, support means; a pair of plates each having a free edge portion adjacent a free edge portion of the other plate, said plates being mounted on said support means movable between an operating position in which said edge portions define a thread passage therebetween having a cross-section larger than that of said thread, but smaller than that of a thickened portion thereon, and a deflected position; means for yieldably maintaining said plates in said operating position, said plates moving from said operating position to said deflected position when a thickened portion of said thread engages said free edges; and quality control means cooperating with at least one of said plates and arranged to be actuated when the latter moves from said operating position to said deflected position.

2. Device according to claim 1; and further comprising means mounting said plates for pivotal movement about a pair of parallel axes located in a plane substantially perpendicular to the thread run.

3. Device according to claim 2, wherein said edge portions are constituted by notches formed in the free adjacent edges of said plates, said notches defining said thread passage.

4. Device according to claim 3, wherein said notches in said edges are right angled and together form a square thread passage.

5. Device according to claim 3, wherein said plates overlap at said free edges, and wherein said notches are deeper than the overlap; and further including means for changing the distance between the parallel axes on which the plates are pivoted whereby to adjust the crosssection of said thread passage.

6. Device according to claim 1, said means for yieldably maintaining said plates in operating position comprising spring means connected to said plates and biased so as to move said plates from said deflected to said operating position, and stop means for limiting movement of the plates under the influence of said spring means beyond said operating position.

7. Device according to claim 2, wherein said means for mounting said plates for pivotal movement about a pair of parallel axes comprises a pair of substantially parallel shafts and bearings rotatably supporting said shafts, and wherein said means for yieldably maintaining said plates in said operating position comprises a pair of spiral springs, respectively attached at one end to said shafts and with the other end to a support means.

8. Device according to claim 1, wherein said quality control means comprise a counting means which is actuated whenever at least one of said plates is moved to said deflected position.

9. Device according to claim 1, wherein said quality control means comprise a thread cutting means which is actuated whenever at least one of said plates is moved to said deflected position.

10. Device according to claim 1, wherein said quality control means include an electric circuit, at least one contact in said circuit and co-operating with at least one of said plates to be closed thereby when said plate is moved to said deflected position.

11. Device according to claim 10; and further including amplifier means in said circuit for amplifying the current flowing through said circuit.

References Cited UNITED STATES PATENTS 1,823,720 9/1931 Baldwin 28-61 2,640,252 6/1953 Abbott 2864 3,154,943 11/1964 Garrett et al. 73-160 FOREIGN PATENTS 27,038 12/ 1902 Great Britain.

LOUIS K. RIMRODT, Primary Examiner. 

